1. Field of the Invention
This invention relates to ground fault circuit breakers, and more particularly to the contacts for a ground fault test circuit on a printed circuit board which also serves as the spring for the test button.
2. Background Information
Ground fault circuit breakers combine a conventional circuit breaker which responds to overcurrent conditions and short circuits with a ground fault detection circuit which trips the breaker in response to ground faults. The addition of the ground fault detector to the conventional small circuit breaker used in residential and light commercial and industrial applications is complicated by the limited space available in such breakers which are designed for installation in a standardized load center or panel board.
U.S. Pat. No. 4,081,852 discloses such a ground fault circuit breaker in which the circuit breaker mechanism is mounted in one compartment within a molded housing and the ground fault detector is mounted in an adjacent compartment. In the '852 patent, the ground fault detector includes a test circuit activated by a test button for testing the operation of the ground fault detector. The ground fault detector is constructed of a number of discrete components including a leaf spring contact which biases a test button to the off position. This movable contact and the fixed test button contact are connected to the other components in the test circuit through discrete wires.
Commonly owned U.S. patent application Ser. No. 676,150, filed on Mar. 27, 1991 and entitled "Dual Wound Trip Solenoid" discloses a two pole ground fault circuit breaker in which the ground fault detector circuit is implemented on a printed circuit board mounted in a compartment within the molded housing. The spring contact for the ground fault test button of this circuit breaker is similar to that in the '852 patent and is connected to the components on the printed circuit board through discrete wires.
There is a need to simplify the design of these mass-produced ground fault circuit breakers to reduce component and labor costs. This includes simplifying the ground fault test circuit.